Make some arguments of FocusController functions references.

Source/core/dom/Element.h

Index: Source/core/dom/Element.h
diff --git a/Source/core/dom/Element.h b/Source/core/dom/Element.h
index c77f7ed27ccf08aa26365ac1e8f861f131ad7163..62e268b042e585e0e0fbcfd0654aef5a2dc85f86 100644
--- a/Source/core/dom/Element.h
+++ b/Source/core/dom/Element.h
@@ -826,11 +826,21 @@ inline bool isShadowHost(const Node* node)
     return node && node->isElementNode() && toElement(node)->shadow();
 }
 
+inline bool isShadowHost(const Node& node)
+{
+    return node.isElementNode() && toElement(node).shadow();
+}
+
 inline bool isShadowHost(const Element* element)
 {
     return element && element->shadow();
 }
 
+inline bool isShadowHost(const Element& element)
+{
+    return element.shadow();
+}
+
 inline bool isAtShadowBoundary(const Element* element)
 {
     if (!element)